EREZ CROSSING, Gaza Strip — Israeli Defense Minister Ehud Barak ordered the army today to allow into Israel any of the hundreds of Gazans holed up at a fetid crossing who might desperately need medical treatment.

Additionally, Israeli officials allowed all foreign nationals in the Hamas-controlled Gaza Strip to cross over to Israel.

Israeli aircraft, meanwhile, fired missiles at two rocket launchers in northern Gaza, in the first aerial attack since Islamic Hamas militants took over the coastal strip late last week. No injuries were reported. Earlier in the day, Israeli tanks entered southern Gaza, and four people, including at least two militants, were killed in an exchange of fire, Palestinian hospital officials said.

Hamas' defeat of security forces from the rival Fatah faction has left many Gazans anticipating further chaos and violence.